X-ray spectral signatures of the cold, hot, and ... · X-ray spectral signatures of the cold, hot,...
Transcript of X-ray spectral signatures of the cold, hot, and ... · X-ray spectral signatures of the cold, hot,...
Cloud formation and acceleration in AGN
X-ray spectral signatures of the cold, hot, and intermediate phases from a clumpy AGN outflow
Daniel Proga & Tim Waters University of Nevada, Las Vegas
These calculations were performed on the Institutional Computing clusters at Los Alamos National Lab
Synthetic UV/X-ray absorption lines from 1st principles
2. Photoionization calculations
For these SEDs, we used XSTAR to determine… i. The heating & cooling rates of the photoionized plasma (see S-curves below) ii. The opacity to spectral lines, i.e. the force multiplier (blue curves below)
Let us focus on 2 ions in particular i. CIV - M(t) > 1 for ii. OVIII - significant opacity for Figure from Dannen et al. (2019)
T [K]
Figure from Dannen et al. (2019)
XraysUV
Saturation of thermal instability (TI) is a cloud formation process, but it also naturally leads to cloud acceleration (Proga & Waters 2015).
v
Basic principle
4. Synthetic absorption lines
Here we show the obscured and unobscured SEDs for NGC 5548 obtained by Mehdipour et al. (2015)
1. Dannen, Proga, Kallman & Waters, Photoionization calculations of the radiation force due to spectral lines in AGNs, 2019, ApJ, 882, 992. Dyda, Dannen, Waters, & Proga, Irradiation of Astrophysical Objects: SED and flux effects on thermally driven winds, 2017 MNRAS,467, 41613. Mehdipour, M. Kaastra, J.S., Kriss, G.A., et al., Anatomy of the AGN in NGC 5548 I., 2015, A&A, 575, A224. Proga & Waters, Cloud Formation and Acceleration in a Radiative Environment, 2015, ApJ, 804, 1375. Waters, Proga, Dannen, & Kallman, Synthetic Absorption Lines for a Clumpy Medium: a spectral signature for cloud acceleration in AGN?, 2017 MNRAS, 467, 3160
References
Governing equationsThese are the basic equations of multiphase gas dynamics:
where the radiation force is given by (see Proga & Waters 2015),
Modeling approach: Local box
simulations of UV and X-ray
irradiated plasma
~ days to weeks
Using Athena++, we performed simulations similar to Proga & Waters (2015) but for the SEDs above using a fully self-consistent pipeline.
Upper panels: phase diagram showing a scatter plot of how gas spans the S-curve (top), density and column density (middle), and the absorption measure distribution (AMD; bottom). Lower panel: column density along the right vertical edge of the domain.
3. Hydrodynamical simulations
Using a post-processing routine that again interfaces with XSTAR to compute the opacity of a given ion at every grid zone, we compute absorption line profiles of common doublet lines using the techniques developed by Waters et al. (2017).
Left panels: Density maps with velocity vectors overlaid at times 18, 24, & 40 as before. Right panels: Synthetic absorption lines. Red and blue colors denote the longer and shorter wavelength components of either doublet line. Due to partial covering, the strength of the CIV lines anti-correlate with those of the OVIII lines as the cloud is disrupted from radiation forces.
1. Observed SEDs
Image credit: Wikipedia Commons
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